A binuclear metallocene complex bridged by a functional group shows excellent properties as a catalyst (M. A. Mansour et al. at J. Am. Chem. Soc. 1998, 120, 1329-1330; and J. C. Vickery et al. Angew. Chem. Int. Ed. Engl. 1997. 36, 1179-1181). Also, it was found that a dimeric palladium compound bridged by a functional group has excellent activity than a palladium acetate compound in the Heck reaction (G. Dyker at Journal of Organometallic Chemistry 1998. 555 141-143).
U.S. Pat. No. 5,233,093 discloses an improved allyl alcohol hydroformylation process and a catalyst therefor. The process employes a catalyst system comprising a Group VIII metal carbonyl complex catalyst, a trisubstituted phosphine, a neutral Group VIII(a) metal complex co-catalyst, and optionally, a diphosphinoalkane. The bimetallic catalyst systems give high selectivity.
U.S. Pat. No. 5,567,847 discloses a process for the production of amines by the catalytic disproportionation of a feedstock containing a primary amine to produce a reaction product containing a secondary amine. The patent resides in the use of a bimetallic catalyst comprising nickel or cobalt in combination with rhodium, palladium, ruthenium or platinum.
Korean Patent Application No. 98-21032 discloses new catalysts having at least two cycloalkanedienyl groups, which are synthesized by bridging metallocene moleculars with an ancillary ligand having at least two functional groups. The catalysts have higher activity than conventional catalysts.
The present inventors have developed a method of preparing new metallocene complexes with high activity, such as bimetallic complex, trimetallic complex, tetrametallic complex, etc. The method of preparing the metallocene catalysts comprises reacting a compound having at least two functional groups with a metal compound of Group IIIB-VIII of the Periodic Table having at least one cycloalkanedienyl group.